[PATCH 1/2] drm/amdgpu: fix start calculation in amdgpu_vram_mgr_new

[Alex Deucher]

On Tue, May 10, 2022 at 7:36 AM Christian König
<ckoenig.leichtzumerken at gmail.com> wrote:
>
> We still need to calculate a virtual start address for the resource to
> aid checking of it is visible or not.

Does this fix a known issue or is it just something you noticed?

>
> Signed-off-by: Christian König <christian.koenig at amd.com>
> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 22 +++++++++++++-------
>  1 file changed, 14 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> index 49e4092f447f..51d9d3a4456c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
> @@ -496,16 +496,22 @@ static int amdgpu_vram_mgr_new(struct ttm_resource_manager *man,
>                         list_splice_tail(trim_list, &vres->blocks);
>         }
>
> -       list_for_each_entry(block, &vres->blocks, link)
> -               vis_usage += amdgpu_vram_mgr_vis_size(adev, block);
> +       vres->base.start = 0;
> +       list_for_each_entry(block, &vres->blocks, link) {
> +               unsigned long start;
>
> -       block = amdgpu_vram_mgr_first_block(&vres->blocks);
> -       if (!block) {
> -               r = -EINVAL;
> -               goto error_fini;
> -       }
> +               start = amdgpu_vram_mgr_block_start(block) +
> +                       amdgpu_vram_mgr_block_size(block);
> +               start >>= PAGE_SHIFT;
>
> -       vres->base.start = amdgpu_vram_mgr_block_start(block) >> PAGE_SHIFT;
> +               if (start > vres->base.num_pages)
> +                       start -= vres->base.num_pages;
> +               else
> +                       start = 0;
> +               vres->base.start = max(vres->base.start, start);
> +
> +               vis_usage += amdgpu_vram_mgr_vis_size(adev, block);
> +       }
>
>         if (amdgpu_is_vram_mgr_blocks_contiguous(&vres->blocks))
>                 vres->base.placement |= TTM_PL_FLAG_CONTIGUOUS;
> --
> 2.25.1
>